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ld-linux.so.2, the dynamical linker, adds shared libraries to the memoryspace of a program to be started. Its flexibility allows for some environment variables to influence the linking process such as preloading shared libraries as well as defining the path in which the linker will search for the shared libraries. Special care must be exercised when runtime-linking setuid- or setgid-binaries: The runtime-linker must not link against user-specified libraries since the code therein would then run with the elevated privileges of the suid binary. The runtime-linker as used in the SuSE distributions ignores the content of the critical environment variables if the specified path begins with a slash ("/"), or if the library file name is not cached (eg it is contained in a path from /etc/ld.so.conf). However, Solar Designer has found out that even preloading glibc- native shared libraries can be dangerous: The code in the user-linked library is not aware of the fact that the binary runs with suid or sgid privileges. Using debugging features of the glibc (and possibly other features) it is possible for a local attacker to overwrite arbitrary files with the elevated privileges of the suid/sgid binary executed. This may lead to a local root compromise.
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-----BEGIN PGP SIGNED MESSAGE-----
______________________________________________________________________________
SuSE Security Announcement
Package: glibc (shlibs)
Announcement-ID: SuSE-SA:2001:01
Date: Friday, January 26th, 2001 15:40 MET
Affected SuSE versions: 6.0, 6.1, 6.2, 6.3, 6.4, 7.0
Vulnerability Type: local root compromise
Severity (1-10): 6
SuSE default package: yes
Other affected systems: most Linux/glibc based systems
Content of this advisory:
1) security vulnerability resolved: glibc
problem description, discussion, solution and upgrade information
2) pending vulnerabilities, solutions, workarounds
3) standard appendix (further information)
______________________________________________________________________________
1) problem description, brief discussion, solution, upgrade information
ld-linux.so.2, the dynamical linker, adds shared libraries to the
memoryspace of a program to be started. Its flexibility allows for
some environment variables to influence the linking process such as
preloading shared libraries as well as defining the path in which
the linker will search for the shared libraries. Special care must
be exercised when runtime-linking setuid- or setgid-binaries:
The runtime-linker must not link against user-specified libraries
since the code therein would then run with the elevated privileges
of the suid binary.
The runtime-linker as used in the SuSE distributions ignores the
content of the critical environment variables if the specified path
begins with a slash ("/"), or if the library file name is not
cached (eg it is contained in a path from /etc/ld.so.conf).
However, Solar Designer has found out that even preloading glibc-
native shared libraries can be dangerous: The code in the user-linked
library is not aware of the fact that the binary runs with suid or
sgid privileges. Using debugging features of the glibc (and possibly
other features) it is possible for a local attacker to overwrite
arbitrary files with the elevated privileges of the suid/sgid binary
executed. This may lead to a local root compromise.
To eliminate these problems, we provide update packages that completely
disregard the LD_* variables upon runtime-linking of a binary that has
an effective uid different from the caller's userid.
Download the update package from locations desribed below and install
the package with the command `rpm -Uhv file.rpm'. The md5sum for each
file is in the line below. You can verify the integrity of the rpm
files using the command
`rpm --checksig --nogpg file.rpm',
independently from the md5 signatures below.
SPECIAL INSTALL INSTRUCTIONS:
==============================
The glibc (the shlibs package) is an intrinsic part of the GNU/Linux
operating system since most binary executables are dependent on
the shared libraries from that package. For this reason, special care
must be taken while updating the shlibs package.
After downloading the binary rpm files, make sure that your system is
idle by bringing it down to Single User Mode (`init 1´). If this is not
applicable for operational reasons, then keep your machine as calm as
possible while you perform the update. In particular, make sure that
no shell scripts are running during the update.
Install the package using the command
rpm -Uhv package-rpm-file
Do _NOT_ interrupt the operation of the rpm command!
After the installation, execute the commands
ldconfig # alternatively, use SuSEconfig
/sbin/init u # will restart init
At this point, the update is done.
On low-memory machines a reboot is advisable to free the memory that
is used by the old memory-mapped libraries.
Note 1:
The upcoming SuSE-7.1 distribution is based on glibc-2.2. This
distribution is not affected by the security problems in glibc as
discussed in security forums.
Note 2:
The source rpm for the shlibs package is called "libc*.rpm".
Multiple binary rpm packages are being generated from this source
rpm package. These include: localedb, nssv1, shlibs, timezone.
To get a fix for the runtime-linker related security issue (topic
of this announcement), it is only necessary to update the shlibs
binary rpm package.
SuSE-7.0
ftp://ftp.suse.com/pub/suse/i386/update/7.0/a1/shlibs-2.1.3-190.i386.rpm
94ccbb80d2841f08f2b7322671d6e7f3
source rpm:
ftp://ftp.suse.com/pub/suse/i386/update/7.0/zq1/libc-2.1.3-190.src.rpm
3d15b6ffff534f0bf705882dbd8a2551
SuSE-6.4
ftp://ftp.suse.com/pub/suse/i386/update/6.4/a1/shlibs-2.1.3-155.i386.rpm
bc03f1a6f32a66958128e9450e355698
source rpm:
ftp://ftp.suse.com/pub/suse/i386/update/6.4/zq1/libc-2.1.3-155.src.rpm
e8f2aa8d32122edfbe3c436a52abb847
SuSE-6.3
ftp://ftp.suse.com/pub/suse/i386/update/6.3/a1/shlibs-2.1.2-48.i386.rpm
8d572332c67b488e5d64a8d4d3274e90
source rpm:
ftp://ftp.suse.com/pub/suse/i386/update/6.3/zq1/libc-2.1.2-48.src.rpm
8e1f861112f4a921ea4c7b5631304ee6
SuSE-6.2
ftp://ftp.suse.com/pub/suse/i386/update/6.2/a1/shlibs-2.1.1-30.i386.rpm
b6b4cfe73e46c5b3bd5b626d68dfa584
source rpm:
ftp://ftp.suse.com/pub/suse/i386/update/6.2/zq1/libc-2.1.1-30.src.rpm
67fcd70b40f145b5f40b86f7254e35be
SuSE-6.1
SuSE-6.0
The rpm packages are being produced as this announcement is written.
The md5sums for these rpm packages will be provided on the ftp-server,
signed with the security@suse.de pgp key below.
Sparc Platform:
SuSE-7.0
ftp://ftp.suse.com/pub/suse/sparc/update/7.0/a1/shlibs-2.1.3-155.sparc.rpm
6b000a6278366c6da4b719d2f62ad7a4
source rpm:
ftp://ftp.suse.com/pub/suse/sparc/update/7.0/zq1/libc-2.1.3-155.src.rpm
e845606be9c9aca72213e4c5f1f32290
AXP Alpha Platform:
SuSE-7.0
ftp://ftp.suse.com/pub/suse/axp/update/7.0/a1/shlibs-2.1.3-155.alpha.rpm
2df813e3c08b52e3f914c591efc742d4
source rpm:
ftp://ftp.suse.com/pub/suse/axp/update/7.0/zq1/libc-2.1.3-155.src.rpm
9cb7a6e5981112da6d702916d453b419
SuSE-6.4
ftp://ftp.suse.com/pub/suse/axp/update/6.4/a1/shlibs-2.1.3-155.alpha.rpm
0636c2cddf131e76c19e154619a65bd8
source rpm:
ftp://ftp.suse.com/pub/suse/axp/update/6.4/zq1/libc-2.1.3-155.src.rpm
39fd3b8e7e4054bc7a333a831e99e6fd
SuSE-6.3
ftp://ftp.suse.com/pub/suse/axp/update/6.3/a1/shlibs-2.1.2-48.alpha.rpm
f9713bc945bf7f98527d2fdfbe756dfb
source rpm:
ftp://ftp.suse.com/pub/suse/axp/update/6.3/zq1/libc-2.1.2-48.src.rpm
af2eb3df9d83f8f8ca13526046a3a539
SuSE-6.1
ftp://ftp.suse.com/pub/suse/axp/update/6.1/a1/shlibs-2001.1.17-0.alpha.rpm
4a0033c4ec32ef0e79fc1b7a83692738
source rpm:
ftp://ftp.suse.com/pub/suse/axp/update/6.1/zq1/libc-2000.9.5-0.src.rpm
11871baa8279f8c0c79f6c9d95ca531c
PPC Power PC Platform:
SuSE-7.0
ftp://ftp.suse.com/pub/suse/ppc/update/7.0/a1/shlibs-2.1.3-173.ppc.rpm
8d9d27a8fba22de4df5cd4700a541ad9
source rpm:
ftp://ftp.suse.com/pub/suse/ppc/update/7.0/zq1/libc-2.1.3-173.src.rpm
89946b9a2bb7c545a1761a84ebd979ab
SuSE-6.4
ftp://ftp.suse.com/pub/suse/ppc/update/6.4/a1/shlibs-2.1.3-190.ppc.rpm
383bb49a2f6a3e83a9c2ed3eea30dc99
source rpm:
ftp://ftp.suse.com/pub/suse/ppc/update/6.4/zq1/libc-2.1.3-190.src.rpm
91ed7087165b74383cddb556abc07402
______________________________________________________________________________
2) Pending vulnerabilities in SuSE Distributions and Workarounds:
This announcement is followed by a sequence of more announcements
to address the ongoing security problems as discussed in public
security forums. In particular, there are temporary file races in
multiple packages (we collect and address them in a single
announcement to keep the noise low), format string bugs, as well
as a man-in-the-middle attack in the kdesu program and a single-byte
buffer overflow. The next announcenemts will contain more information
on these topics.
Please stay tuned.
______________________________________________________________________________
3) standard appendix:
SuSE runs two security mailing lists to which any interested party may
subscribe:
suse-security@suse.com
- general/linux/SuSE security discussion.
All SuSE security announcements are sent to this list.
To subscribe, send an email to
<suse-security-subscribe@suse.com>.
suse-security-announce@suse.com
- SuSE's announce-only mailing list.
Only SuSE's security annoucements are sent to this list.
To subscribe, send an email to
<suse-security-announce-subscribe@suse.com>.
For general information or the frequently asked questions (faq)
send mail to:
<suse-security-info@suse.com> or
<suse-security-faq@suse.com> respectively.
===============================================
SuSE's security contact is <security@suse.com>.
===============================================
Regards,
Roman Drahtmüller,
SuSE Security.
- -
| Roman Drahtmüller <draht@suse.de> // "Caution: Cape does |
SuSE GmbH - Security Phone: // not enable user to fly."
| Nürnberg, Germany +49-911-740530 // (Batman Costume warning label) |
- -
______________________________________________________________________________
The information in this advisory may be distributed or reproduced,
provided that the advisory is not modified in any way.
SuSE GmbH makes no warranties of any kind whatsoever with respect
to the information contained in this security advisory.
Type Bits/KeyID Date User ID
pub 2048/3D25D3D9 1999/03/06 SuSE Security Team <security@suse.de>
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This archive was generated by hypermail 2.1.0
: Mon Jun 04 2001 - 18:25:15 PDT
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